Note 18 - California First National Bancorp (Parent Only) Financial Information (Details) - Condensed Balance Sheets (Parentheticals) - $ / shares	Jun. 30, 2015	Jun. 30, 2014
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred stock, shares authorized	2,500,000	2,500,000
Preferred stock, shares issued	0	0
Common stock, par value (in Dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	10,459,924	10,459,924
Common stock, shares outstanding	10,459,924	10,459,924
Parent Company [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred stock, shares authorized	2,500,000	2,500,000
Preferred stock, shares issued	0	0
Common stock, par value (in Dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	10,459,924	10,459,924
Common stock, shares outstanding	10,459,924	10,459,924